Method and apparatus for drying paper



5 Sheets-Sheet 1 EUGWW! H. H. HANSON METHOD AND APPARATUS FOR DRYING PAPER Filed June I322 I J/mmm Sept. 15. 1925 .Sept. 15, I925 H. H. HANSON 7 METHOD AND APPARATUS FOR DRYING PAPER Filed June 9'; 1922 3 Sheets -Sheet 2 d/gaaild /dmm Sept. 15, 1925 1,553,443

' H. H. HANSON METHOD AND APPARATUS FOR DRYING PAPER Filed June 9, 1922 3 Sheets-Sheet 3 v 590 fl/dzmwe Patented Sept. 15, 1925.

UNITED STATES 1,553,443 PATENT: OFFICE.

HUGO H. HANSON, O1 BOSTON, MASSACHUSETTS, ASSIGNOR TO EASTERN MANUFAC run'rne COMPANY, 'SETTS.

OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHU- marnon AND APPARATUS more. DRYING PAPER.

. Application filed June 9, 1922. Serial No. 566,952; I

To all whom it may concern:

Be it known that I, HUGO H. HANSON, acitizen of the United States, residing at f Boston, in the county of- Suffolk and State 5 of Massachusetts, have invented .new and useful Improvements in Methods and Apparatus for Drying Paper, of which the following is a specification.

In the manufacture of high grade writing 1- paper such as bond, ledger,'and'linen finish paper, it has been customary to dry the paper, after the sizing operation, in lofts, where the sized sheets, arraii d in packets, are hung over poles for some ours. This is 'a slow process, non-continuous,-and produces a pronounced curvature along the median line of each sheet where it is supported by th pole, but gives otherwise desirable results since thepaper is'not under restraintduring the 'dryingoperation so that it may shrink and produce:- a strong paper of desirable cockled surface. 7

Various attempts have been made to dry the paper in a web by a. continuous process,

one of these, which is quite 'successfuhbeing disclosed in the patent application of Hugo H. Hanson and Wilfred A. Wylde for method of and apparatus for drying paper, filed January 26, 1921, Serial Number 440,-

173. In the machine disclosed in this application the paper is passed in the form of a continuous web over a plurality of horizontal. rows of rollersv in a drier casing, which are driven at progressivelydecreasing speeds, the decreasing speed of the rolls allowing for the shrinkage of the paper'as it dries so that it may be under substantially-- no restraint as it passes through the drier. Withthis apparatus the process is rendered continuous, it being, possible to utilize sufficient heat without damage to the paper to complete the drying operation for any'portion of'the paper within one minute. It is found, however, that the paper weaves back 7 and forthas it passes through this apparatus, so that it is wound or reeled irregularly after leaving it. His usual to allow about one inch, trim for the edges of a web of paper, but. as this weaving or tracking'eifect is sometimes as much as six inches, a trim of this amount mightbe necessary in some cases to avoid the production of narrow sheets during the subsequent slitting and cutting operations.

.th at the complete no stretch since the paper mustbe dried the less the slack the less the lateral travel method and apparatus by which the amount The cause of this weaving or tracking may be explained by comparing the paper web to an endless belt passing over pulleys. If the pulleys are uncrowned and one sidev of the belt is a little longer than the other, the belt will run off the pulley at the shorter edge where-the tension is greater. As the paper is made on a paper machine, it is almost certain to have a longer and a shorter edge because of the dilferent drying conditions in the drying cylinders, a more permancntstretch being produced on the faster drying edge of the paper. The paper on the paper machine would therefore tend to travel toward the opposite side of the'paper machine, but is prevented from doing so by the tension on the web which is sufficient to stretch the shorter edge to cause the paper to run true. When the tension is relieved the elasticityof the fibers causes this more highly stretched edge to contract so web still has a longer and a shorter edge. 1

In the continuous loft, as disclosed in the application above referred to, there can be so under as little restraint as possible, so that there is a definite tendency of the paper to travel toward the shorter edge. If this tendency were constant, it might readily be provided for by setting over the reel a corresponding amount. It is not constant h-owever.

After considerable experimentation it has been discovered that the weaving is caused by variations in the slackness of the web,

and vice versa. The variation an sla-ckness is caused by variationsin shrinkage of the web during its travel through the/drier due to many variable conditions, such as paper as it comes from the 'p'aper'machine, changes in the amount of size picked up in the sizing tub, changes in temperature inside the loft and variations in air currents and humidity. These and other causes are too difiicult of sufficiently accurate control for the practical elimination of weaving.

This invention therefore provides a of slack may be mechanically controlled within such limits as to insure asufliciently constant lateral position of the issuing web.

' which is shown in Figure 3. This group accompanying drawings which illustrate an embodiment thereof in which Figures 1 and 1 represent a side elevation of the drier loft, part of the side wall being removed, together with the dry end of a paper machine and a sizing tub, the

parts being shown somewhatconvention-' all Figures 2, 3, and 4 are diagrammatic views of the driving mechanism for the upper, intermediate and lower tiers. of rollers showing the slack indicating mechanism.

Figure 5 is a diagrammatic detail of the driving mechanism.

Referring to Figure 1, at 1 are represent.

ed a pair of drying rolls at the dry end of the paper machine. At 2 is represented a sizing tub through which the web of paper shown in broken lines at w passes from the paper machine and where the size is picked up. From this tub the paper web passes while supported on various tiers of rollers,

shown and described in the application above referred to. The roups of rollers of the different tiers are driven with relatively adjustable speeds, there being shown for this purpose in each of Figures 2, 3, and 4, a shaft extending longitudinally of the machine, thisshaft being driven as shown in Figure 2 through a pair of belted cone pulleys 31 from a main power shaft 32. The roller 5 at the entrance to theloft is driven at a constant speed relative to the shaft 32, it being shown as driven b beveled gears from the driving cone pu ey 31'.

The first set of feed rollers 6 are shown as driven by means of suitablev gearing through a jack shaft 32 belted at 33 to a pulley on the shaft 30. The rollers 7 as 'shown are driven at a somewhat lower speed through a shaft 34- geared to the shaft 30 and belted by a belt 35 on the shaft of one of the rollers 7, the other rollers being driven therefrom. The group 8 is shown as driven through a variable Speed mechanism comprising a pair of belted cone pulleys 36 from the shaft 30. The group 10 of the intermediate tier is also driven. through these same variable speed pulleys, but: preferably between a pair of rolls 3, over a guide roll at a lower rate of speed than the group 8.

4, and into the end of the continuous loft or drier through a narrow slot in the end wall thereof. The paper first passes over a feed roller 5 and then over a series of feed rollers arranged in groups, this being indicated for the top tier in Figure 2, the first group comprising those marked 6, the second group at 7 and the third group shown .at 8. Beyond the group 8 the paper, as shown, passes over an end roll 9 and then passes back beneath the uppertier of feed rollers over a lower tier, the grouping of ing comprises a serieslO, the second series ,11, and the third series 12. At the'endof the series 12 is positioned a large roller 13 over which the paper passes down to the lowest tier, the grouping of which is shown in. Figure 4. This grouping comprises three series of rollers 14, 15, and 16. After leaving the group 16 the paper passes under a guide roller 17, then over a pair of winding feed rollers 18 and to the reeling mechanism shown at 19, the winding rollers 18 being used to apply tension to the web as it is reeled by the reeling mechanism. While as shown the feed rollers are arranged in three tiers, this ,is merely for convenience in order to shorten up the mechanism. They could, if desired, be in a single tier or in any number desired.

In Fi ures 1 and 1 areshown a series of blower fans 20 by means of which currents of heated air are passed over the paper wet lower-speed than the group 14 or the group 11. THef'group 16 is driven through a variable speed mechanism comprising cone pulleys 4O actuated by the shaft 30 and which also drives the winding rolls 18.

Preferably the groups of rollers are driven "at a slightly higher rate than the speed of movement of the paper, though the end pulleys 5, 9, 13, and 18 which act more effectivelyto impart driving impulse to the pagroup 15 is also belted to. the shaft 34 by a belt 38 tojbe drivenat a per should be driven at the speed at which it is desired to drive the piper. In this apparatus, however, it may seen that the relative speeds of driving of the rollers may be regulated according to the speed of drying, to permit the paper to shrink while substantiall unrestrained, it being under comparative y slight tension by the feeding mechanism.

- In order to determine the slackness of the paper, a mechanism has been provided for concentrating the slackness at a single point in the form of a loop, the size of which may be readily observed by the operator so that the relative speeds of the various groups of rollers may be adjusted to cause-this loop to remain of practically constant size. For

this purpose, in the construction shown, jets of air are employed to be projected against the web of paper to form a looptherein be- 7 tween a pair of rollers as at 1 1' of Figure 1.' Such a jet isshown in Figure 2 at 50, comprising a pipe extending'acr'oss the web substantially parallel to a pair of rollers 8 and between them, and having a slot in the side facing the web. Asimilar pipe is shown at 51 in Figure 3, extending across the web between the groups of rollers 10 and 11.

Any suitable 'means (not shown) may be used to supplyair under pressure 'to these pipes, supply pipe 500 and 510 leadin therefrom to the jets 50 and 51' being indicated; Since most of the drying efi'ect occurs at the upper and intermediatetiers, means for localizing the slack are shown as applied to'these tiers only, though such means might be applied wherever desired.

and 51 the loft casing is preferably provided with a window as shown at 52in Figure 1 so that the size of the loop, or the depth to 'slackness inthe paper.

"-rate oftravel of the various rollsin con which it extends below the plane of the topof the feed rollers may be readily 'observed by the operator, who may adjust the relative speeds of the groups of rolls to produce a nearly constant size of loop, so producing a substantially constant amount of By adjusting the formity with the size ofthe loop in this manner, it has been found possible to control the extent of side travel of the. web as it passesthroug'h'tlie machine'to hold it at a substantially, constant. value so that' weav- 2. The method of-oontrolling the ing is eliminated. I

Having thus described an embodiment of this invention it "should. be "evident that many modifications and'changes might be made therein without departing. from its claims..-

Ifclaim: g J 1.- The method of preventing weaving of.

spirit "orTs cope1as defined by the; appended a paper-web traveling continuouslynn a "path, while mechanically substantially un-. restrained, through a drying chamber, which consists in relatively adjustin in dif-. ferent portions of the length of sai chamher the rate of feed of said .web.

travel of a paper web traveling continuously in'a path throu h a .drier casing while mechanicall 'ntially' unrestrained, which eoiislsts in gathering the slack of said web at a point along its lengthin said drier, observing the amount ofrsaid slack,

and regulating the relative speed of feed in different portions of casing in. ac-

Opposite the ends of these air pipes 50 out substantial restraint, whic controlling the amount of slack in said web within said drier.

of slack in saidweb within said casing.

cordance with such observations to control the amount of said slack.

3. The method of preventing weaving of i a paper web traveling continuously through a drier casing havin a series of driven rollers therein on whi'c the web is supported "recting a jet against said web between a pair of rollers to gather the slack of said .web into a loop, andregulating the relative speed of rotation of said rollers so as to maintain said loop .of a substantially constant size.

5.The method of controlling the lateral positionof a continuous paper web issuing from a drier in which it is supported withand by which it is. fed substantially other- 7 out substantial restraint, whlch com rises.

varying the relative speed of travel 0 said.

Web along its path within said drier.

6. The method of controllingthe lateral position of a continuous paperweb issuing from a drier in which it is sup rted withcomprises 7. A drier comprising a series of rollers for supporting a continu-- ous web pamingthrough' said casing, means fordriving said rollers at variable relative "speeds to feed said web in substantially unrestrained conditionv through said casing,

and means forconcentrating slack in said web between a pair of adjacent rollers n a loop to indicate to an observerthe amount -of such slack.

8. A drier comprising a. casing a series of rollers therein for s11 porting a continuous web pasing throng said casing, means-for driving said rollers atvaricasing having a I able relative speeds to feed said web in sub-' stantiallyunrestrained condition insaid casingya'nd means for'indicating the amount 9. A drier comprising a casing having a f series of rollers therein for supporting a continuous web passing throu h said casing, means for rotating said ro lers at variable relative speeds to feed said webinsubstantially unrestrained condition through said casing, a pipe extending laterally. of t eresaid web and having a slot directed toward between a pair of adjacent rollers, and means for supplying air to said pipe to blow said web between said ad'acent rollers to localize slack therein in a p.

10. A drier comprising a casing having a series of rollers therein for supporting a continuous web passing through said casing, means for rotating said rollers at variable relative speeds to feed-said web in substaritially unrestrained condition through- ..said casing, a pipe extending laterally of said web .and having a slot directed thereto ward between a pair of adjacent rollers, means for supplying air to said. pipe to blow said web between said adjacent rollers to localize slack therein in a loop, and a window in said casing through which the size of said loop may be observed.

' 11. A drier comprising a casing having a plurality of series of rollers therein for successively supporting and feeding a web through said casing, means for driving said rollers at differentially adjustable speeds whereby said web may be fed in substantiall unrestrained condition, and means for loca ing the slack of said web on certain of said series whereby the amount of slack may be determined.

12. A drier comprising a casing having a plurality of series ofrollers therein for successively supporting and feeding a web through said caslng, means for driving said rollers at difi'erentially adjustable speeds -whereby said web may be fed in substantially unrestrained condition, and means for forming a loop in the web between adjacent rollers of certain'of said series to take up slack in the web.

-13. A drier comprising a casing having a plurality of series of rollers therein for successively supporting and feeding a web through said casing, means ijor driving said rollers at difi'e're'ntially adjustable speeds whereby said webmay be fed in-- substantially unrestrained condition, means for forming a loop in the-Web between adjacent rollers of certain of said series to take up slack in the Web, and means by which .the-

amount of such slack shown by the length I of loop may be observed.

14:. A drier comprising a casing having a plurality of series of rollers therein for successively supporting and feeding a web through said casing, means for drivlngsaid rollers at difl'erentially adjustable speeds whereby said web may be fed in substan-.

tially unrestrained condition, means for blowing against said web between adjacent rollers of certain of said series to localize the slack ofsaid web in a loop between said rollers, and means by which the length of said loop may be observed.

In testimony whereof Lhave aflixedmy signature.

I HUGO 'HANson. 

